1. Field of the Invention
The present invention relates to a scanning type exposure apparatus which transfers a pattern of a mask to a photosensitive substrate, an exposure method, and a method for producing a device.
2. Description of the Related Art
In the photolithography step for producing, for example, a semiconductor device or element, an exposure apparatus is used, wherein a pattern of an image (pattern image) of a mask (or a reticle) is projected onto a photosensitive substrate (for example, a wafer coated with a photoresist) via a projection optical system to perform the exposure. In the ordinary exposure apparatus, one pattern is formed on one shot area on the photosensitive substrate. On the other hand, in order to improve the throughput, an exposure apparatus of the double exposure system has been suggested, wherein a same shot area on a photosensitive substrate is subjected to the scanning exposure with two patterns by using a so-called two-headed type projection optical system (see, for example, Japanese Patent Application Laid-open No. 2007-201457).
In recent years, it has been investigated to large-size the photosensitive substrate to be used for the photolithography step. However, in the conventional technique as described above, when the number of shot areas provided on the photosensitive substrate is increased as the photosensitive substrate is large-sized, the throughput of the photolithography step is lowered approximately in proportion to the ratio of the increase.
An object of aspects of the present invention is to provide an exposure apparatus, an exposure method, and a method for producing a device which make it possible to achieve the improvement in the throughput in relation to the scanning exposure.